1. Field of the Invention
The present invention relates to a printing apparatus and a printing method in which an image is printed on a sheet using a plurality of print sections positioned so as to be deviated from each other in a sheet conveying direction.
2. Description of the Related Art
In general, a conveying path along which a sheet is conveyed through a position opposite to a print section includes an upstream side conveying roller positioned on an upstream side of the print section in a sheet conveying direction and a downstream side conveying roller positioned on a downstream side of the print section in the sheet conveying direction. A speed at which the sheet is conveyed by the downstream side conveying roller is set higher than a speed at which the sheet is conveyed by the upstream side conveying roller. Furthermore, a sheet sandwiching force exerted by the downstream side conveying roller and a pinch roller opposite to the downstream side conveying roller is set weaker than a sheet sandwiching force exerted by the upstream side conveying roller and a pinch roller opposite to the upstream side conveying roller. Thus, the downstream side conveying roller conveys the sheet while causing slippage between the downstream side conveying roller and the sheet. As a result, the sheet can be adequately conveyed with no slack.
Japanese Patent Laid-Open No. H08-337011(1996) describes a printing apparatus including a first print section configured to print an image on one surface of a sheet and a second print section configured to print an image on the other surface of the sheet, the first and second print sections being positioned so as to be deviated from each other in the sheet conveying direction. A first conveying path along which the sheet is conveyed to the first print section includes an upstream side conveying roller and a downstream side conveying roller. Similarly, a second conveying path along which the sheet is conveyed to the second print section includes an upstream side conveying roller and a downstream side conveying roller. In the first print section, the sheet is conveyed with no slack by the upstream side conveying roller and downstream side conveying roller in the first conveying path. Similarly, in the second print section, the sheet is conveyed with no slack by the upstream side conveying roller and downstream side conveying roller in the second conveying path.
However, when the sheet is conveyed from the first conveying path to the second conveying path, the sheet is conveyed by the downstream side conveying roller in the first conveying path and the upstream side conveying roller in the second conveying path. In this case, the former downstream side conveying roller otherwise positioned on the downstream side in the conveying direction is positioned on the upstream side in the conveying direction. The latter upstream side conveying roller otherwise positioned on the upstream side in the conveying direction is positioned on the downstream side in the conveying direction. Thus, the slippage otherwise caused between the former downstream side conveying roller and the sheet does not occur, and the sheet may be slack between the former downstream side conveying roller and the latter upstream side conveying roller. Such slack of the sheet particularly causes disturbance when a high-quality image is printed and also causes a sheet jam.